The Rectilinear 2D Mesh

Figure C.32 shows the basic layout of the rectilinear
2D waveguide mesh. It can be thought of as simulating a plane using
1D digital waveguides in the same way that a tennis racket acts as a
membrane composed of 1D strings.

At each node (string intersection), we have the following simple formula for the
node velocity
in terms of the four incoming traveling-wave components:

By continuity of velocity in a series connection (all string endpoints
must move together at the node), the outgoing velocity-wave components
must be given by